Use of Hot Water Pressure Wash Surface Preparation and HRCSA Coatings in Bridge Maintenance

(c)1036338 (wo) 3In this Transportation Research Synthesis (TRS), state-of-the-art practice of highway bridge maintenance painting using high-ratio calcium sulfonate alkyd (HRCSA) and hot water pressure wash (HWPW) is reviewed and different state DOTs are surveyed. In summary, low-toxic HRCSA causes less pollution, eliminates waiting time between layers of coatings, and performs well for corrosion prevention. However, like any other protective coating system, optimum HRCSA performance requires following the manufacturer\u2019s specifications. Contrary to what the term \u201cone-coat system\u201d may suggest, HRCSA application is a multi-step process that requires HWPW surface preparation. Based on the literature review and survey findings, without further testing and trials, HRCSA is recommended only for maintenance tasks that can strictly fulfill the manufacturer\u2019s specifications, i.e., an initial HWPW followed by the multi-step process and sufficient drying time before an extreme weather event

Aiaa-2002-1416 Thermal/mechanical Response And Damage Growth In

In order to increase the reliability of the next generation of space transportation systems, the mechanical behavior of polymeric matrix composite (PMC) materials at cryogenic temperatures must be investigated. This paper presents experimental data on the residual mechanical properties of a carbon fiber polymeric composite, IM7/PETI-5 both before and after aging at cryogenic temperatures. Tension modulus and strength were measured at room temperature, --196C, and --269C on five different specimen ply lay-ups, [0 ] 12 , [90] 12 , [45] 3S , [25] 3S and [45,90 3 ,-45,0 3 ,- 45,90 3 ,45]. Specimens were preconditioned with one set of coupons being isothermally aged for 555 hours at C in an unloaded state. Another set of corresponding coupons were mounted in constant displacement fixtures such that a constant uniaxial strain was applied to the specimens for 555 hours at --184 C. The measured lamina level properties indicated that cryogenic temperatures have an appreciable influence on behavior, and residual stress calculations based on lamination theory showed that the transverse tensile ply stresses could be quite high for cryogenic test temperatures. Microscopic examination of the surface morphology showed evidence of degradation along the exposed edges of the material due to aging at cryogenic temperatures

Desorption of Emulsifiers From Polystyrene Latices Followed By Spectroscopic Techniques

The desorption of emulsifier from the particle surface of latices prepared by emulsion polymerisation has been followed by spectroscopic techniques: transmission IR, X-ray photoelectron spectroscopy (XPS) and static secondary ion mass spectrometry (SSIMS) -fast atom bombardment mass spectrometry (FAB-MS). In IR spectra, the extra band at 1710 cm-1 due to carboxylic groups originating from the emulsifier is fortunately visible because it is located within a window of the polystyrene peaks. XPS is a valuable surface method of analysis (contrary to IR). Nevertheless, for the latices considered here, it is impossible to extract from the very intense carbon peak information concerning variation in the carboxyl groups, which amount to less than 1%. Another important method for surface analysis is static-SIMS, which allows detection of elements and molecular species present in the first few layers with a detection limit which is less than 10(-4)%. FAB-MS permits the detection of the parent ion of the emulsifier employed. Freeze-dried powders of latices extensively purified with mixed-bed ion-exchange resins were studied for us using FAB-MS at UMIST in Manchester (UK). A comparison is made of the results obtained with these three spectroscopic techniques